A multi-position shifting switch is a switch, which can perform a shift connection with respect to two or more electric powers or two or more loads, and can control the operation of plural equipments, further is widely utilized in daily lives and industrial production such as power stations, orbit stations, high-speed railway locomotives, subway locomotives and ships. The switch generally comprises positions of plural manual control modes and a stop control mode. A locking mechanism of the multi-position shifting switch is a main carrier and significant part to protect the switch, and to avoid misoperation after the multi-position shifting switch is shifted into a specific mode position. A lock function of the locking mechanism is one of the important indicators to judge whether it is excellent or not that the performance of the locking mechanism. With the acceleration of development in industrialization and informatization, equipments automatically controlled by computers are widely applied in electrical control area, therefore the multi-position shifting switch should also comprise an automation control mode position, that the operation of equipments could be controlled by computers. And when the equipments need to be emergency stopped while the multi-position shifting switch is in the automation control mode, the multi-position shifting switch should be able to shift from the automation control mode position into a stop control mode position.
As shown by FIG. 18, prior art discloses a locking mechanism 300, which performs a lock controlling with respect to the control mode positions in the multi-position shifting switch. When the locking mechanism locks the multi-position shifting switch into the automation control mode position, a key needs to be inserted into a key cylinder 301 and rotated to actuate a controlling cam 302, whose protrusion is thus deflected towards a locked body 307 and pushes a moving body 303 towards a resist convex component 305. Then a mesh top 304 on the moving body 303 is actuated to mesh with a location tooth 308 on the locked body 307, therefore a position shift based on the coaxial rotation of the locked body 307 and a switching shaft 306 cannot be carried out. In such situation, manual operation on the operation modes cannot be accepted or responded. Such locking mechanism can prevent man-made misoperation on the equipments when the automation control mode is locked. In the case of emergency, when the multi-position shifting switch needs to be shifted into the stop control mode position from the automation control mode position immediately, the key needs to be inserted into the key cylinder 301 again, and then the protrusion of the controlling cam 302 is deflected away from the locked body 307. Thus the resist convex component 305 pushes the moving body 303 away from the locked body 307, and actuates the mesh top 304 on the moving body 303 to separate from the location tooth 308 on the locked body 307. Along with the coaxial rotation of the locked body 307 actuated by the switching shaft 306, the multi-position shifting switch is consequently shifted into the stop control mode position from the automation control mode position. However, with respect to such locking mechanism, once the multi-position shifting switch is locked in the automation control mode, without the key the multi-position shifting switch cannot be shifted into the stop control mode position, that all the equipments can be stopped. So in the case of emergency such as barriers appear right in front of high-speedy running railway trains or subway trains, which need to be emergency stopped, since the multi-position shifting switch with the aforesaid locking mechanism cannot be shifted without the key, the equipments cannot be stopped and a disastrous consequence may occur such as equipments trouble, equipments paralysis even casualties. Therefore, such locking mechanism is not suitable for the multi-position shifting switch provided with the automation control mode position, that the operation of equipments is automatically controlled by the computer.
To overcome such disadvantage of above locking mechanism, a prior art solution is to add a protecting electric system into the circuit of the multi-position shifting switch, which makes the structure of the locking mechanism more complicated, and increases the cost of equipments manufacture, further is too tedious to install and utilize.